The proposed application is a competitive supplement to the NINR funded project titled "Nursing Management of IBS: Improving Outcomes". In the United States, it is estimated that 10-20% of the population experience symptoms compatible with a diagnosis of irritable bowel syndrome (IBS). IBS is a functional condition characterized by change in bowel patterns, (e.g., constipation, diarrhea), interfering with functional activities and increasing health care utilization. Current recommended therapies include diet manipulation, self-management, psychotherapy, and motility and pain modulation via pharmacological therapy. The purpose of the parent project funded in 2002 is 1) to determine whether the CSM intervention is equally effective in men and peri- and postmenopausal women and 2) to determine whether the CSM intervention is as effective when delivered over the telephone as compared to a face-to-face approach. A three-group randomized clinical trial with longitudinal follow-up will be used to test the effectiveness of a face-to-face versus telephone comprehensive self-management (CSM) program relative to a usual care control group. Outcome variables will be measured during the assessment phase (T1) then 6 months (T2) and 12 months (T3) after the randomization phase. The primary aim of this supplement is to compare the distribution of SET polymorphisms across predominate bowel pattern subgroups and gender in people with IBS. We hypothesize that the distribution of SERT polymorphisms (5'-flanking promoter region [5-HTTLPR] and in exon 2 [VNTR]) will differ across predominate bowel pattern subgroups and the distribution of SERT polymorphisms will differ by gender. Exploratory aims of this study include: 1) Evaluate the relationship of SERT polymorphisms to symptom experiences and psychological profile; 2) Test whether the degree of improvement in response to the CSM therapy differs by SERT polymorphism; and 3) Evaluate the relationship of platelet rich plasma 5-HT levels to SERT polymorphisms, predominate bowel pattern. This study will provide information on the potential role of serotonin processing in IBS as well as potential gender and bowel symptom predominance. Such results may ultimately be used to tailor therapies for this common health problem. [unreadable] [unreadable]